Northern blot technique is used in the detection of: (D. REPEAT JIPMER 2011)
**Core Concept**
The Northern blot technique is a laboratory method used to detect and study **RNA molecules**. It involves the separation of RNA samples according to their size, followed by their transfer to a membrane and hybridization with a labeled probe. This technique is essential in molecular biology for analyzing **gene expression**.
**Why the Correct Answer is Right**
The correct answer is related to the detection of RNA, which is the primary application of the Northern blot technique. This method is specifically designed to identify and quantify **RNA sequences** in a sample. By using a labeled probe that is complementary to the target RNA sequence, researchers can detect the presence and abundance of specific **mRNA** or other types of RNA.
**Why Each Wrong Option is Incorrect**
**Option A:** This choice is incorrect because it is not directly related to the primary use of Northern blotting.
**Option B:** Similarly, this option is incorrect as it does not accurately represent the main application of the Northern blot technique.
**Option C:** This choice is also incorrect because it is not the correct representation of what Northern blotting is used for.
**Clinical Pearl / High-Yield Fact**
The Northern blot technique is crucial for understanding **gene expression patterns** and can be used to diagnose diseases caused by abnormalities in RNA. Remembering that Northern blot is for RNA, while Southern blot is for DNA, is a key point for exams.
**Correct Answer:** D. RNA